Methods in Anopheles Research - MR4

Chapter 6 : Dissection Techniques6.6 Examination of Ovaries by Tracheal Distension to Determine ParityPage 2 of 47. Multiple pairs of ovaries can be mounted on a single microscope slide, but ensure that all the sampleshave dried before viewing them under a microscope.8. View under a compound scope at 200 X magnification. Locate the tracheoles and determine if thespecimen is nulliparous (Figure 6.6.2) or parous (Figures 6.6.3 and 6.6.4).Figure 6.6.1. Dissection of female terminaliaunder stereoscope. The ovaries are circled.Terminalia and segments VII and VIII are visible inthe upper right hand corner.Figure 6.6.2. An example of a tightly coiledtracheole called a “skein” is shown inside the circle.This is a nulliparous female.Figure 6.6.3. Inside the circle is the loosestructure of the tracheoles after oogenesis. This isreferred to as the extended state. This female isparous.Figure 6.6.4. Both types of tracheoles are seen inthis photograph. The circle on the left side shows atightly coiled skein while the circle on the rightshows an extended tracheole. Even though both arepresent in this example, this female would beconsidered parous.ReferencesDetinova TS (1962) Age grading methods in Diptera of medical importance with special reference tosome vectors of malaria. Monograph Series, World Health Organization 47:1-216